The present invention relates to signal-seeking receivers which are completely electronic in nature and which are utilized for a plurality of various applications where a single radio frequency band or a number of radio frequency bands are monitored for locating and receiving predetermined signal frequencies.
Electronic signal-seeking receivers have conventionally been comprised of a plurality of local oscillators which are respectively tuned to a predetermined frequency so that the receiver can receive such predetermined frequencies to the exclusion of all others. Such receivers, in the past, have required a separate crystal for each frequency to be received. These crystals, one which is required for each frequency to be received, are expensive, and thus proportionately increase the cost of such receivers.
Secondly, such receivers have been severely limited in the number of frequencies which can be received, since such receivers are typically broad band in nature and do not have the sensitivity to receive all of the frequencies in the HF, VHF and UHF bands.
The prior art receivers are either limited to a single frequency band, i.e., HF, VHF or UHF, or if such receiver is capable of receiving signals from two or more bands, the receiver has always utilized a separate antenna for each such band to be received. Coupled with each antenna is the required RF amplifier and mixer stages. This also increases the cost, and ultimately the sales price, of such receivers which makes them undesirable for use by the majority of consumers.
It is, therefore, desirable to provide a signal-seeking receiver which does not utilize a plurality of specially configured oscillators containing crystals to select the desired signal frequencies; which relies only on a single antenna for reception of the signals in a plurality of radio bands, minimizes the content and the cost of the electronics heretofore involved.